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0. A. COLBY.

ELECTRIC FURNACE.

APPLICATION msn un 4. |920.

Patented Nov. 14, 1922.

WITNESSES:

mvENToR 0rd A. COJ/ Bv ATTORNEY f electriceresstance:typerendait has tor.- ique ot its objects totiprovide a turnace inwbach a new; and useful Another-.object ofy vide asolid-blockresistor-of refractory velecmeans forconducting theicurre4 from the resistor,

dition, ,prevent rapid, deterioration of the,

Patented Nov. i4, 1922.

one A. coLBY, 'or IRWIN',

rENNsYLvaNrA,` AssrGNon'ro wns'rmononsn ELECTRIC a MANUFACTURNG CoMraNr, A ooarone'rron'orrENNsYLvANm.

y YEuro'rmc FURNACE.

Application .filed May 4, .1920.' eraliNof'B'iSg'iSS.

Yior/,Zifurhomf't may concern; Be it known that 4I, ORA -A.,COLr, a cltizenot the United States,and.aresident of lrwimin the countyo and State' of Pennsylvania, have ,invented Improvement in Electric Furnaces, of which the following isa speci lication. 4 p i j f My. -inventiong relates to electric furnaces and particularly tovmelting furnaces of the lYestmoreland the resistor'zisv located. tact -ivith a container meltedw v in close tbermalaconnventien nlroimproved t to and which means Willrnladtrical-conducting material: and Y resistor blocks; i` 'N MVS i, Inpracticing my 1nvent1on,.1.p,rovide a :suitable (container. for the metal .being` the same 1n a refractory -.in,9t; befsubietedffw .fthe-.high temperature 0f melted, mounting casing, a block resistor located beneath and supporting said container, hoppers adjacent the ends of said resistor blocks, solid terminal electrodes projecting into said hoppers, and masses of granular electricalconduct ing material in said hoppers electrically connecting the electrodes and the resistor blocks.

In the single sheet of drawings, Figure 1 is a top plan view of a furnace embodying my invention; Fig. 2 is a View, partly in rear elevation and partly in section, on the line Il-H of Fie. 1, and Fig. 3 is a crosssectional view of the same furnace on the line TIL-HI of Fig. 1.

The supporting structure of the furnace comprises an exterior metal casing or frame i which encloses an outer shell 2 'built up or' heat-insulatingr brick. and an inner shell 3 huilt up of fire brick. A number ot bricks or slabs 4; of a suitable highly refractory material partly surround and support a resistor 5 which comprises one or more bricks or blocks of carborundum or silicon carbid. A container G for the metal to be heated may consist @t any suitable material used for such purposes but l prefer to use alundum sintercd in place` as this material has a high heat conductivity and is not attacked by molten non-ferrous metals. The

` d irrnnediately beneath, and in closether-mal. contact with` the bottom of the container 6 sc tliat the heat generatelsiby gtheV resistor IWill-.readily flow 4throughAthebcttoxnothe container and fiptoytbecontents thereof. The container 6 'risqproyided-gwith `a; .suitable extension? in which isf iformed, a'ponring trough 8 for the rnoltenlfmetalwpposite, and -adjacent to, eachgend gigi-,lie resistor-blocks 5, a hopper` or well 9 is formedin the brick 'work, the .resistor hlocksextending a short distance intoathese ihopperlsor furells. f. At the `bottom of Ileach hQpPQr iisg :placed za l rterminal .elec- `;tij'oide v:u rhiclzi, comprises a 'solid block of graphite orzaninrphouscarbon. A terminal plate L1 isisuitably secured tothe outer end .of ieachpof-the electrodes -lQand projects through the casing 1 iordconnectiom to an electric supplyylcircuitffconductor. (not atelectrode lOis made frein-the resistor :proper and .will Ytlwrefore y lresistor".5 iis f locate the resistor itself.

A mass 12 of electrical-conducting granular material, such as graphite or coke, is placed in each of the hoppers 9 and, as its cross-section is made relativelyT large` it provides a c'urrent path of relatively low resistance between the electrode 1() and the resistor blocks There a solid refractory resistor is used to obtain a relatively high temperature, as is required to melt certain non-ferrous alloys, a relatively rapid deterioration of the resistor blocks occurs at the place where contact is made with a metallic conductor terminal, especially if this Contact is exposed to the atmosphere and if it is subjected to a relatively high temperature. This deterioration is prevented by using Finely divided electrical-conducting material to provide numerous current paths to the resistor blocks. Some of the granular material oxidizes during the operation of the furnace so that the contact resistance increases but the open hoppers permit of repacking, the granular material when any appreciable amount thereof has been oxidized and of removingr and completely renerving the material Whenever necessary. The granular material also protects the terminal electrodes l0 from being overheat-ed,

:is it n'ovides a. lowresistance-clirrent path there rom.

A :suitable ('m'ir nimnlmr (not shown) muy lie used, if desired, to prevent radiation of heat from the' upper .surface of the furnace resin3 :and from the container itself (hiring thc operation of' the furnace.

A plurality of suitable brick piers 13 Iare provided which carry suitable bearing members 14 for (zo-operation with short shaft ex tensions l5 Secnred'to the metal casing 1 to permit of tilting the enti'iefnrnaceto pour the m'l'ten metal.

l thnsrproide an electrical furnace in which af-bloelg resistor is 'used fto generate the heat and to siili'lieit theeontztier and in wl'h'themethob conducting the current to andifr'olnithe resisterpermi'ts 'osubstantia-l'ly f uninterrupted operetienv v@1% the tion-ef the 'resistii blocks.'

.While 4'I haveshewn f1-:specific erfilco'diment' omy invent-ien, vafds changes may 'ffrnce with a relatively 'small deteriorabmad'e' therein withqut departing from the 'spirit and' seo of'myi'nventin, end I dsi'rethat on-l; such limitations shall be pfeeedthereon as are imposedby tle prior r't'or are'specifically s t frtli lin the eppended claims:

I claim as my inventionf:

sa id hoppers lniterial interposed between each 0f the electrodes and the resistor to prevent overhcutiner nf thc electrodes.

yIn an electric melting furnace, the cmnlaiimtion with a container of refractory nmteriul, of :i resistor located beneath, und Suppmtingsuirl containensaid resistor comprising solid blocks of refractory electricalconducting material in contact with one anothen lioppers located opposite the ends of tlnj resistor: solid carbonaceous terminal electrodes in said hoppen; and a mass of electrics.l-contluctilfigl granular material in adapted to conduct current from said electrodes to seid resistor and to prevent overheating and consumption of seid electrodes( 3A In an electric melting furneie; the

combinationwith." a container, e vrefflectory casing for' saielcontain'er,"and Ineens' fori tilting said continelf `and said casing-of a resi-stein loveetzdbeneath 'Said container' and comprising sojld blocksof refe-acte electricaleon'lucting material to const tute a support for said container, hopperslfed' opposite the ends ofsa'd resirxstpi',- solit c arbonaceous 'terminal electrodes at the A'bottom cf'seid hoppers, and a massfof'electriclseon ducting grnulam'material -in'said hoppen-S T920:- ORA-A. ICOBBY'J 

